Study about Doping Ion La3+ onto Surface of Pyrolusite Ore for Removing Simultaneously Both Fluoride and Phosphate from Wastewater

Nguyen Thi Hue,Nguyen Hoang Tung

doi:10.1155/2017/4893835

Nguyen Thi Hue, Nguyen Hoang Tung

Open Access

https://doi.org/10.1155/2017/4893835

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Abstract

Lanthanum has been doped onto the surface of the natural Pyrolusite for simultaneous removal of phosphate and fluoride in aqueous solution. The adsorbent characterization of the materials was observed by the SEM, BET, and XRD techniques. The dynamics and isotherms models of fluoride and phosphate adsorption, with respect to pH, pHPZC, adsorbent dose, and effect of coexisting ions, were studied. The results showed that lanthanum doped Pyrolusite ore (LDPO) relatively highly adsorbed amount of phosphate and fluoride from aqueous solution. Phosphate and fluoride removal efficiencies of LDPO are approximately 97% and 95%, respectively. Pseudo-first order for kinetic studies of phosphate and fluoride removal of the LDPO was observed with high correlations for fluoride but weak correlations for phosphate. However, pseudo-second order for kinetic studies was high correlation for both phosphate and fluoride. The phosphate and fluoride adsorption capacities of the LDPO significantly decreased with the existence of coions (sulfate, chloride, and nitrate) in the aqueous solution.

Highlights

Extensive research has been performed to eliminate phosphate or fluoride from aqueous solution due to their hazardous effect caused to the human health
Several methods such as adsorption [1,2,3,4,5], precipitation [6,7,8,9], ion exchange [10, 11], reverse osmosis [12, 13], nanofiltration membrane [14, 15], Donnan dialysis [16, 17], and electrodialysis [18, 19] techniques have been used for removal of either phosphate or fluoride
The results indicated that La-doped Pyrolusite ore (LDPO) 1 : 1, which removes both phosphate and fluoride to the highest degree, gives pH of treated water at the neutral level (7.5)

Summary

Introduction

Extensive research has been performed to eliminate phosphate or fluoride from aqueous solution due to their hazardous effect caused to the human health. Several methods such as adsorption [1,2,3,4,5], precipitation [6,7,8,9], ion exchange [10, 11], reverse osmosis [12, 13], nanofiltration membrane [14, 15], Donnan dialysis [16, 17], and electrodialysis [18, 19] techniques have been used for removal of either phosphate or fluoride. Various adsorbents, activated alumina [24,25,26], activated carbon [27, 28], low cost adsorbents [5, 29,30,31], rare earth oxides [32, 33], and natural products [29, 30, 34, 35] like tree bark, groundnut husk, sawdust, rice husk, and so forth, have widely been used for removal of either phosphate or fluoride

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